The first image from Cal Cactus would be O. polyacantha var. erinacea, and the plants are of the long flexible-spined form that was [also] named O. ursina. I've seen this specimen. It is I think correctly labelled, but very atypical. The spines are usually much longer and very beautiful yellow or white often with nearly black bases. It is the southern subspecies of O. engelmannii, but has never been officially published as such.

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Species Notes: The pictures below from Great Basin National Park show both the yellow and pink flowering forms growing side by side. I took notice of this while on location and tried to find evidence of a hybrid color between the two. I did not find one plant in the area that was not fully yellow or fully pink. In one of the images you will see a peach or orangish colored flower. This is a yellow flower that has faded and not a cross. Many cactus flower will fade to a different color as they age.

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